New submission from Vignesh vigne...@mail.med.upenn.edu:
I have a python script which runs a particular script large number of times
(for monte carlo purpose) and the way I have scripted it is that, I queue up
the script the desired number of times it should be run then I spawn threads
and each thread runs the script once and again when its done.
Once the script in a particular thread is finished, the output is written to a
file by accessing a lock (so my guess was that only one thread accesses the
lock at a given time). Once the lock is released by one thread, the next thread
accesses it and adds its output to the previously written file and rewrites it.
I am not facing a problem when the number of iterations is small like 10 or 20
but when its large like 50 or 150, python returns a KeyError: 51 telling me
element doesn't exist and the error it points out to is within the lock which
puzzles me since only one thread should access the lock at once and I do not
expect an error.
This is the class I use:
class errorclass(threading.Thread):
def __init__(self, queue):
self.__queue=queue
threading.Thread.__init__(self)
def run(self):
while 1:
item = self.__queue.get()
if item is None: break
result = myfunction()
lock = threading.RLock()
lock.acquire()
ADD entries from current thread to entries in file and
REWRITE FILE
lock.release()
--
components: IDLE
messages: 105981
nosy: Vignesh.K
priority: normal
severity: normal
status: open
title: Threading and KeyError: 51
versions: Python 2.5
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http://bugs.python.org/issue8751
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